Portable stove

ABSTRACT

A portable stove includes a frusto-conical body and a grid carried within the body together with an optional cooking surface for the smaller end of the body and stands to elevate the larger end of the body to facilitate establishing an air flow into the body. By rolling a flat piece of metal that has folds on both ends until the folded ends are interlocked, the stove&#39;s body is formed. Squeezing the formed body releases it to return to a flattened configuration for storage. The components of the stove can thus be stored in a compact configuration such as in a backpack. An optional oven includes a cooking chamber within a housing. The oven rests on the body and redistributes heat from the burning fuel inside the body to the cooking chamber base, body and lid so that it bakes evenly. The housing confines the heat to the chamber for improved cooking efficiency.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a contination in part of application Ser. No.10/783,050, filed Feb. 20, 2004 now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to portable stoves and ovens forcooking using available combustible solid fuels.

Many people throughout the world use electric or gas ovens, microwaveovens and stovetops for cooking. However, many more do not. Stoves andovens that use wood, propane, charcoal, peat, dung, or chemicalcombustibles are often used out of convenience or necessity. Forexample, those hiking long distances may build campfires for cooking andfor warmth. Campers may include small portable propane stovesspecifically for camping among their camping gear.

Not everyone has a choice in the way to cook. Many people inunderdeveloped countries cook in primitive ways, perhaps using campfiresor simple structures in which to burn whatever solid fuels areavailable. Many times these primitive heat sources are inefficient,consuming a lot of fuel for the amount of cooking actually being done.

However, even when the most modern cooking appliances are available, theresults are not always optimal. The taste of food is often better whenthe right combinations of browning and residual moisture content areobtained. Those combinations do not always result from the use of themost modern cooking appliances.

Thus their remains a need for a better way to cook, particularly forthose who do not have access to conventional stoves, ovens, microwaveovens and the like, whether by choice or not, and preferably a way tocook that is more energy efficient and also, ideally, more easilyportable.

SUMMARY OF THE INVENTION

According to its major aspects and briefly recited, the presentinvention is a portable stove. The present stove in all embodiments is asmall stove for simple outdoor cooking and, in one embodiment, baking.

An important feature of the present invention is that the stovedisassembles without tools into a series of flat components that can bestored or carried easily with minimal space requirements.

Another important feature of the present invention is that it ispreferably made to have a frusto-conical shape that has two advantages.This shape is very stable and is more energy efficient. The presentstove also has a cooking surface that takes the heat, concentrated bythe frusto-conical shape, and delivers it to the food-holding containerplaced on the surface, thereby avoiding wasted heat thrown to the sidesof the container.

Still another important feature of the present invention is the use ofcopper to transmit heat in a controlled manner. The heat follows copperreadily, more so than many other metals, delivering it to where it isdesired and thus wasting less heat.

Another feature of the present invention is an oven that surrounds abaking chamber with heat from the stove below it and thus bakes withsurprisingly good results.

Other features and their advantages will be apparent to those skilled inthe art of lamp design from a careful reading of a Detailed DescriptionOf The Invention accompanied by the following drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective, partially exploded view of a stove according toa first preferred embodiment of the present invention;

FIG. 2 is a perspective, partially cut-away view of a stove according toan alternative preferred embodiment of the present invention;

FIG. 3 is a perspective view of a stove according to a first preferredembodiment with alternative stands;

FIG. 4 is a perspective view of the stove of FIG. 3 shown disassembled,according to the first alternative embodiment of the present invention;

FIG. 5 is a perspective view of an alternative stove according to asecond preferred embodiment of the present invention;

FIG. 6 is a cross sectional side view of the alternative stove shown inFIG. 5; and

FIG. 7 is a perspective, partially exploded view of a stove having analternative cooking surface configuration.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a device for cooking, that is, for serving as aheat source for food and beverages, which device will be referred tosimply as a stove. The present stove can heat the bottom of a containerof food in the same fashion as a stovetop does or, in an alternativeembodiment, it can surround a food item, in a container or otherwise,with heat in order to bake the item, as in an oven. It has a secondaryfunction as serving as a heat source for individuals.

Referring now to FIGS. 1–4, the present stove, generally referred towith reference number 10, includes a body 12 and a fuel support grid 14.It may also include a cook surface 16 and stands 18. Stands 18 may haveslits 24 formed in them to receive body 12.

Body 12 is generally cylindrical in shape but is preferably slightlyfrusto-conical in shape so that the diameter of its top 30 is smallerthan the diameter of its bottom 32 in order to concentrate heat and bemore stable. Body 12 is made of a single piece of sheet metal withcomplementary folds 34, 36 at opposing edges that can be interleaved forbody 12 to define and hold the cylindrical or frusto-conical shape butalso to allow it to be unfolded flat when it is to be stored, perhapsslightly curved inside a backpack. The term cylindrical will be usedherein to include frusto-conical unless the latter term is specificallyused.

It is important to allow air to flow into body 12 and out of body 12.Air flowing in brings oxygen for combustion; air flowing out takesexhaust gases with it. Accordingly, body 12 can have small cutoutportions 40 at bottom 32 (FIG. 1) for mating with stands 18 to elevatestove 10 above a surface on which it is placed. Correspondingly,upstanding tabs 42 at top 30 define openings 44 through which exhaustgases may exit body 12 at top 30.

FIG. 2 shows an alternative method, to that shown in FIG. 1, forelevating body 12 in order to admit air for combustion. Base supportrods 230 may be inserted through holes 232 formed in body 12 just belowfuel support grid 14. One end of rods 230 extends into body 12 andthrough holes in grid 14; the other remains outside body 12 and acts asa leg for standing body 12 above the ground. All of the rods 230 may bemoved inward as desired to adjust the height of the stove and thusadjust the draft and rate of combustion. Additionally, if used on aslope, some of the rods may be moved inward to keep the stove andcooking utensil level.

Fuel support grid 14 is a disk with plural holes formed therein,preferably a circular disk of expanded metal. Grid 14 has extensions 50at several locations around its periphery that extend through holes 52in body 12, when extensions 50 are brought into registration with holes52, for supporting grid 14 at a distance above bottom 32 of body 12.Grid 14 is adapted to hold fuel while permitting air to flow up into thebottom opening of body 12, through grid 14 and the fuel, and out the topopening of body 12, thereby admitting air and creating a draft withinbody 12 to facilitate combustion. The frusto-conical shape of body 12also facilitates the establishment of a draft by forcing theacceleration of the heated air upwards from cutout portions 40 or thespaces between stands 18 at bottom 32 upwards within body 12 to exit atopenings 44 a top 30. Holes 52 may be round or rectangular and should besized to make it easy to put extensions 50 through them as body 12 iscurled around grid 14 during assembly and squeezed to releaseinterlocking folds 34, 36. Also, extensions 50 and holes 52 arepreferably deployed about body 12 to provide stable support for grid 14,most preferably three extensions 50 and three holes 52 at approximately120 degree intervals are sufficient.

Cook surface 16 is preferably made of copper or other metal or metalalloy that quickly and readily conducts heat, and has an extendedportion 54 along its periphery to facilitate lifting. Preferablyextended portion 54 has a hole 56 formed near an edge that can be usedin combination with a tool or stick 60 to lift cook surface 16 when itis hot.

Note from the illustration in FIG. 4 that the components of the presentstove 10 can be disassembled without tools and laid flat. Grid 14, cooksurface 16, and stands 18 are already flat. Body 12 cools quicklybecause it is made of metal and can be easily squeezed to releaseinterleaved folds 34, 36. Once folds 34, 36 are released, body 12 can beunrolled from its cylindrical or frusto-conical shape and placed flat.Alternatively, body 12 can be inserted in a backpack so that it followsthe curve of the backpack's sides. Grid 14, cooking surface 16, andstands 18 can be placed in a plastic bag and carried easily in abackpack or one of its pockets. Note that cook surface 16 prevents sootdeposits on cooking utensils and it and the other components of thepresent stove 10 can easily be wiped clean with a damp cloth.

FIG. 5 and FIG. 6 illustrate another embodiment of the presentinvention. In this embodiment, there is a stove 70 having a body 72 anda grid 74 that function in the same manner as stove 10 with its body 12and grid 14. Other than being dimensioned to be somewhat larger, theprimary differences are a lower air-controller 80, a fuel hatch 82, abase 84, and an optional oven 86.

Lower air-controller 80 is a collar 90 with a series of holes 92 formedtherein. A series of holes 94 are also formed in body 72. Holes 92 canbe brought into and out of registration with holes 94 to increase ordecrease the flow of air into the interior of body 72. Collar 90 is madeto be easily rotatable coaxially with body 72 but can be secured bytightening a bolt 96 running through flanges 98 at the end of collar 90,thereby pulling flanges 98 together and tightening collar 90 to body 72.Collar 90 is preferably dimensioned to be below grid 74 and near bottom100 of body 72.

Fuel hatch 82 is intended to allow the user to add fuel after setup.Hatch 82 is preferably hinged to body 72 in such a way that it can belifted to an open position or lowered to a closed position easily. Mostpreferably, when lifted, the top edge of hatch 82 pivots about a ringhinge 110 and can be inserted partially into the hatch opening where itwill remain in the lifted position against body 72 until lowered. Fuelhatch 82 is of course preferably located above grid 74 in the side ofbody 72.

Above fuel hatch 82 is a support surface 116 that is a flat, disk-shapedpiece of sheet metal having a hole formed therein large enough so thatit slips over a top 118 of body 72 and comes to rest on the exterior ofbody 72 several inches from top 118. Support surface 116 acts to supportoven 86, as will be described below.

Base 84 has two threaded fittings 124, 126 that receive centering bolts130, 132. Bolts 130, 132 are threaded to threaded fittings 124, 126.Then grid 74 is secured to centering bolts 130, 132 using nuts 104, 106.Body 72 can be fitted over grid 74 and the remaining components placedthereon.

Oven 86 includes a baking chamber 140 and a baking housing 142. Bakingchamber 140 fits within housing 142, which creates a heated environmentsurrounding baking chamber 140. Baking chamber 140 includes acylindrical body 144, base 146 and lid 148. Helping to seal base 146 tobody 144 and body 144 to lid 148 are gaskets 150 and 152, respectively.These are preferably made of copper channel metal but may be made of anyother heat conducting, flexible material. Once body 144 is placed onbase 146, base 146 is secured to lid 148 using thin cables 154 andlatches 156 that pivot to pull cables 154 tight and hold baking chamber140 together. Inside baking chamber is a cooking rack 160 held in placepreferably by chains 162 secured to body 144 using bolts 164. Chains 162allow cooking rack to be adjusted vertically to the proper positionwithin baking chamber 140. Food items such as breads, pies, cakes,casseroles, chickens and potatoes can be baked on rack 160 within bakingchamber 140. The height of rack 160 is preferably set so that the top ofthe food item is an inch or so below lid 148.

Except for lid 148, baking chamber 140 is preferably made entirely ofcopper or other metal or metal alloy that conducts heat readily so thatheat received from the combustion of fuels on grid 74 is transmitted tobase 146 and thence to body 144 and to top 148 quickly so that body 144,base 146 and top 148 radiate heat evenly into the interior of bakingchamber 140. Lid 148 has preferably two layers: a copper lower layer 184and a stainless steel upper layer 186. This combination helps to preventwarping of lid 148 as a result of prolonged exposure to heat.

Housing 142, preferably made of stainless steel or other alloy thatconducts heat less readily than copper or other metal baking chamber 140is made of will tend to hold heat in and surround baking chamber 140with heat. Housing 142 rests on support surface 116 and includes only abody 166 and a lid 168. Support surface 116 has a hole dimensioned toreceive a portion of body 166 so that body 166 extends into housing 142.Preferably lid 168 has a layer for heat insulation 188 on top of it.Smoke and other exhaust gases can circulate within housing 142 (but notenter baking chamber 140) and exit from a gap 170 between supportsurface 116 and body 166. Preferably wedges 172 can be used to enlargegap 170.

A thermometer 174 is important to use, as baking requires a reasonabledegree of control over the temperature inside baking chamber 140.Thermometer 174 extends from outside housing 142 through a first hole176 formed therein into baking chamber 140 through a second hole 180formed therein.

Without wishing to be bound by theory, it is believed that the presentbaking chamber 140 promotes browning without excessive moisture loss.Browning, while nominally improving the appearance of food, alsocontributes to the flavor of food, particularly baked products. TheMaillard reaction, in which amino groups of amino acids, peptides andproteins react with the glycosidic hydroxyl groups of sugars to formbrown pigments, is known to enhance flavor and aroma. The presentchamber 140 has been observed in testing to produce superior browning ofpies, for example, when compared to that achieved using standard ovens.Not only is browning more even, but flavor and aroma is enhanced. It isbelieved that the smaller confines and relatively sealed conditions ofchamber 140 produce this effect. Liquids in the food are not lost ordispersed but are retained to be absorbed by the sugars in the food itemand slow the gelatinization process to become lighter and more tender.

To use stove 70 for baking, a food item such as a pie 182 is placed onrack 160 and lid 148 placed on body 144. Lid 148 is secured to base 146using cables 154 and latches 156 are pivoted closed to pull lid 148 ontightly. A fire is started in body 72 using available fuel such as woodor dried dung by inserting the fuel through open fuel hatch 82 andadjusting lower air controller 80 and upper air controller 84. Anoptional hose 182 that preferably has flexible plastic portion 184 and ametal portion 186 can be used to increase airflow while the fuel iscatching fire by blowing in plastic portion 186 while holding metalportion in holes 92, 94. Once the fire is burning evenly, supportsurface 116 can be put into position and baking chamber placed on top118. Housing 142 is lowered over baking chamber 140 and first and secondholes 176, 180, respectively, are brought into registration by rotatinghousing 142. Once holes 176 and 180 are aligned, thermometer 174 can beinserted. If the temperature reading on thermometer 174 is too low, fuelcan be added and lower air controller 80 adjusted to produce a hotterflame. If the temperature is too high, lid 168 can be lifted for a fewmoments, water can be squirted on the fuel or lower air controller 80adjusted to reduce the amount of air flowing into body 72. Combinationsof these can be used to maintain the temperature inside baking chamberwithin a pre-selected range of temperatures.

Stove 70 can be disassembled into its components and bodies 72, 144, and166 flattened in the same manner as body 12. Bodies 72, 144, 166, allhave seams 190, 192 and 194 that are formed by interlocking folds formedin their respective edges. By squeezing bodies 72, 144, 166, theseinterlocking folds can be unlocked and separated. Once unlocked, bodies72, 144, 166 may be pressed flat. Collars 90 and 120 can be unbolted andopened nearly flat. Thus, stove 70 can be stored in a relatively compactconfiguration for later use, easily re-assembled without tools and usedagain.

FIG. 7 illustrates another embodiment of the present invention wherebybody 72 may be used to convey heat to the surface of a grilling surface220. To achieve this configuration, slots 200 on support bridges 202 arefirst positioned to allow support bridges 202 to rest on the top edge ofbody 72. Support bridges 202 may be joined by their interlocking slots204 to provide stability to the support structure for grilling surface220. Bridges 202 may extend outside the perimeter of the top surface ofbody 72. On the ends of support bridges 202, slotted elevating bolts 210can be positioned, with the ends of bridges 202 being received into theslots of slotted elevating bolts 210, to provide elevated support forgrilling surface 220 above body 72.

It is intended that the scope of the present invention include allmodifications that incorporate its principal design features, and thatthe scope and limitations of the present invention are to be determinedby the scope of the appended claims and their equivalents. It alsoshould be understood, therefore, that the inventive concepts hereindescribed are interchangeable and/or they can be used together in stillother permutations of the present invention, and that othermodifications and substitutions will be apparent to those skilled in theart of lamp manufacture from the foregoing description of the preferredembodiments without departing from the spirit or scope of the presentinvention.

1. A stove, comprising: a frusto-conical body having a smaller topopening and a larger bottom opening; a fuel support grid carried withinsaid frusto-conical body; a cook surface carried on said top opening,said top opening being formed to define tabs between which exhaust gasesexit, said cook surface being carried on said tabs of said top opening;and means for elevating said frusto-conical body so as to admit a draftof air into said frusto-conical body through said bottom opening, passthrough said fuel support grid and exit said top opening.
 2. The stoveof claim 1, wherein said frusto-conical body has an opening formedtherein between said fuel support grid and said top opening, and whereinsaid stove further comprises a hatch covering said opening, said hatchbeing adapted to be lifted to insert fuel through said opening forplacement onto said fuel support grid, wherein said elevating meansfurther comprises at least three rods, and wherein said frusto-conicalbody has at least three holes formed therein between said fuel supportgrid and said bottom opening, said at least three holes being dimensionsfor receiving said at least three rods so that said at least three rodscan be inserted partially into said at least three holes toward and intosaid fuel support grid whereby said at least rods extend laterally andrigidly from said frusto-conical body in order to elevate saidfrusto-conical body and admit said draft of air, said rods being movableinward as desired to adjust the height of the stove and thus adjust thedraft and rate of combustion.
 3. The stove of claim 1, wherein said cooksurface has an edge and wherein a hole is formed therein near said edgefor use in lifting said cook surface 16 when said cook surface is hot.4. The stove of claim 1, further comprising a baking chamber carried bysaid cook surface.
 5. A stove, comprising: a frusto-conical body havinga smaller top opening and a larger bottom opening; a fuel support gridcarried within said frusto-conical body; a cook surface carried on saidtop opening, said top opening being formed to define tabs between whichexhaust gases exit, said cook surface being carried on said tabs of saidtop opening; and means for admitting a draft of air into saidfrusto-conical body, through said fuel support grid and out said topopening, wherein said elevating means further comprises at least threerods, and wherein said frusto-conical body has at least three holesformed therein between said fuel support grid and said bottom opening,said at least three holes being dimensions for receiving said at leastthree rods so that said at least three rods can be inserted partiallyinto said at least three holes toward and into said fuel support gridwhereby said at least rods extend laterally and rigidly from saidfrusto-conical body in order to elevate said frusto-conical body andadmit said draft of air, said rods being movable inward as desired toadjust the height of the stove and thus adjust the draft and rate ofcombustion.
 6. The stove of claim 5, wherein said frusto-conical bodyincludes a first series of holes near said bottom opening and below saidfuel support grid, and wherein said admitting means further comprises acollar encircling said frusto-conical body near said bottom openingbelow said fuel support grid, said collar having a second series ofholes formed therein and being rotatable so that said first and saidsecond series of holes can be placed more or less in registration todefine an air passage into said frusto-conical body below said fuelsupport grid.
 7. The stove of claim 5, wherein said cook surface furthercomprises: a grilling surface; and means for elevating said grillingsurface above said top opening.
 8. The stove of claim 7, wherein saidelevating means further comprises: support bridges crossing said topopening of said frusto-conical body; and bolts carried by and extendingupwards from said support bridges to which said grilling surface can besecured.
 9. The stove of claim 5, further comprising a baking chambercarried on said cook surface.
 10. The stove of claim 9, furthercomprising: a baking housing dimensioned to hold said baking chambertherein; and a support surface having a hole formed therein dimensionedfor receiving a portion of said frusto-conical body, said baking housingresting on said support surface so that said portion of saidfrusto-conical body extends into said baking housing.
 11. The stove asrecited in claim 9, wherein said baking chamber is made of copper. 12.The stove as recited in claim 9, further comprising a thermometerinsertable into said baking chamber and readable outside said bakingchamber.
 13. The stove of claim 9, wherein said baking chamber furthercomprises: means for sealing said chamber; and means for adjustablypositioning food vertically within said chamber.
 14. The stove of claim13, wherein said means for sealing said baking chamber includes plurallatches.
 15. The stove of claim 13, wherein said means for sealing saidbaking chamber includes a gasket.
 16. The stove of claim 5, wherein saidfrusto-conical body has an opening formed therein between said fuelsupport grid and said top opening, and wherein said stove furthercomprises a hatch covering said opening, said hatch being adapted to belifted to insert fuel through said opening for placement onto said fuelsupport grid.
 17. The stove of claim 5, wherein said frusto-conical bodyis formed of a sheet of metal having a first edge and an opposing secondedge, said first and said second edges being folded complementarily sothat said folds interleave to define said frusto-conical shape but alsoto release said folds to open said housing when said housing issqueezed.
 18. The stove of claim 5, wherein said hatch has a top edgeand is secured by said top edge to said frusto-conical body by a hingeand wherein said hinge is dimensioned to allow said top edge of saidhatch to hold said hatch in an opened position to allow fuel to beplaced on said fuel support grid.
 19. The stove as recited in claim 5,further comprising a tube for augmenting air flow admitted into saidfrusto-conical body.